1. Field of the Invention
The present invention relates to a flying head slider for use in a hard disk drive of the swing arm type.
2. Description of the Prior Art
FIGS. 1 and 2 of the accompanying drawings show a hard disk drive of the swing arm type.
As shown in FIGS. 1 and 2, a plurality of vertically spaced magnetic hard disks 2 are mounted on a vertical spindle 1 of a spindle motor (not shown) so that the hard disks 2 can be rotated at a high speed of 3,600 rpm, for example, in the direction indicated by the arrow a (FIG. 1). A plurality of swing actuator arms 4 are swingably mounted on an arm shaft 3. Specifically, the actuator arms 4 comprise respective arms 6 attached to the outer circumference of a boss 5 disposed around the arm shaft 3, and respective suspensions 7 in the form of leaf springs attached respectively to the distal ends of the arms 6. A plurality of flying head sliders 8 are mounted respectively on the distal ends of the suspensions 7. A voice coil attachment arm 9 is mounted on the outer circumference of the boss 5 remotely from the arms 6. The voice coil attachment arm 9 can be angularly moved by a voice coil motor (not shown) to turn the actuator arms 4 and hence the flying head sliders 8 in the directions indicated by the arrows b, c (FIG. 1).
When the hard disks 2 rotate at high speed in the direction a, air flows are developed in the direction a on the surfaces of the hard disks 2 and applied to cause the flying head sliders 8 to float off the surfaces of the hard disks 2 by a slight distance in the order of submicrons against the resiliency of the suspensions 7. While the hard disks 2 are thus rotating, signals can be recorded on or reproduced from the hard disks 2 by magnetic heads on the flying head sliders 8.
The flying head sliders 8 are generally of a dual-rail configuration shown in FIG. 3 of the accompanying drawings, as disclosed in Japanese laid-open patent publication No. 61-57087, for example.
As shown in FIG. 3, the flying head slider 8 includes a slider body 11 having a pair of parallel slider rails 12 on its lower surface which confronts a hard disk 2, with a slider groove 13 being defined between the slider rails 12. The slider rails 12 have lower slider surfaces 14, respectively. A magnetic head 15 is mounted on one of the slider rails 12 so as to lie substantially flush with the slider surface 14 thereof. Each of the slider rails 12 has a pair of slanted surfaces 16, 17 on the opposite ends of the slider surface 14. When the air flow is produced in the direction a and applied to the flying head slider 8 upon high-speed rotation of the hard disk 2, a static pressure is developed on the slider surfaces 14, forcing the slider surfaces 14 and the magnetic head 15 off the surface of the hard disk 2 by a slight distance in the order of submicrons.
The yaw angle of each of the flying head sliders 8 with respect to the air flow in the direction a is selected to be 0.degree. at a radially innermost disk region ID and .alpha..degree. at a radially outermost disk region OD, as shown in FIG. 1. When the flying head slider 8 swings for accessing movement in the direction c from the radially innermost disk region ID toward the radially outermost disk region OD, the distance or height by which the flying head slider 8 floats off the hard disk 2 tends to increase easily. This is because the static pressure developed on the slider surfaces 14 increases at a higher rate in proportion to the linear velocity of the air flow which is maximum at the radially outermost disk region OD than it decreases due to the change of the yaw angle from 0.degree. to .alpha..degree..
Heretofore, it has been impossible to keep the flying head slider 8 floating off the surface of the hard disk 2 by a small distance of about 0.1 .mu.m over a full disk surface range from the radially innermost disk region ID to the radially outermost disk region OD. In the vicinity of the radially outermost disk region OD, the distance by which the flying head slider 8 floats off the hard disk 2 is 0.2 .mu.m or greater, resulting in a large spacing loss which makes it difficult to effect high-density recording of signals on the hard disk 2.